card, a diamond, or a poem

A psychologist conducts a study to investigate the whether women prefer a card, a diamond, or a poem as a wedding anniversary gift.
Each woman is given each type of gift and rates it from 0 to 30.
The higher the rating number, then the more liked is the gift.

13.00    27.00    28.00
20.00    28.00    27.00
25.00    30.00    30.00
17.00    21.00    25.00
10.00    15.00    17.00
11.00    16.00    22.00
26.00    22.00    30.00
14.00    28.00    29.00

1.    What is the independent variable?  How many levels does it have?

Type of gift: card, diamond, poem

2.    What is the dependent variable?


3.    Is this experiment a non-repeated measures ANOVA or a repeated measures ANOVA? Explain your answer?

Repeat because each woman is given each type of gift so each woman gets measured at all levels of the IV

4.    State the null hypothesis and the alternative hypothesis in terms of the type of gift and the ratings.

Ho: Type of gift does not affect ratings
Ha: Type of gift does affect ratings

5.    Write out the null hypothesis and the alternative hypothesis just in terms of the means.

Ho: all the means are the same
Ha: At least two of the means are different

Type of gift will affect ratings

6.    Open a new SPSS file. Enter the data according to your answer to question 3.

7.    Run the appropriate omnibus test, plot the means and run the appropriate post hoc test.

Analyze > General Linear Model > Repeated Measures (within subject factor put gift ; number of levels is 3 > Add > Define (move card diamond poem into within subjects) > Options (check Desc stats, move gift into display means for; check compare main effects; check sidak on confidence interval adjustment > continue > plots (move fit too horizontal axis > Add > Continue > Ok

8.    Do we need to do a Levene’s Test for homogeneity of variances significant? Explain you answer.

No because we have dependent samples

9.    What are the mean ratings for each gift?

Descriptive Statistics
Mean    Std. Deviation    N
Card    17.0000    6.14120    8
Diamond    23.3750    5.75543    8
Poem    26.0000    4.53557    8

10.    What is the Mean Squares Between Groups and what is the Mean Squares Within Groups?

MSBG = 171.4
MSWG = 10.3

Tests of Within-Subjects Effects
Source    Type III Sum of Squares    df    Mean Square    F    Sig.
Gift    Sphericity Assumed    342.750    2    171.375    16.671    .000
Greenhouse-Geisser    342.750    1.351    253.739    16.671    .002
Huynh-Feldt    342.750    1.559    219.871    16.671    .001
Lower-bound    342.750    1.000    342.750    16.671    .005
Error(Gift)    Sphericity Assumed    143.917    14    10.280
Greenhouse-Geisser    143.917    9.456    15.220
Huynh-Feldt    143.917    10.912    13.189
Lower-bound    143.917    7.000    20.560

11.     What is the F-ratio and what is the p-value?

F-Ratio = 16.7 = 171.4 / 10.3
P= .000

12.    Write the results of your omnibus test ANOVA in APA format.

F (DFBG, DFWG) = F-Ration , p <> .05
F (2, 14) = 16.7 , p <> .05

13.     Is the omnibus test significant? Explain your answer.

Yes its significant because P<.05

14.     What does your answer to Question 11 tell you about what you
should do with the null hypothesis and what does it say about the

Reject Ho and at least 2 of the means differ
15.     Look at the post hoc t-tests and compare the means with each other?
NOTE: You should make 3 comparisons.
For each comparison, write down: the two levels of the independent
variable, the two means, the relevant p value and explain why you conclude that the two means are or are not significantly different from each other.

16.    According to the post hoc t-tests, which gift(s) is most liked?


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